S.I.R. 100W SuperLead Schematic pt. II

[giordydiver]

a questione about shield trick and cap grid/plate. if i use a little cap it is installed after or before input resistor? other question, if i use a shield trick what is the right length?

[budubum92]

a questione about shield trick and cap grid/plate. if i use a little cap it is installed after or before input resistor? other question, if i use a shield trick what is the right length?

foget about the cap trick. go with the shield trick.

find a durable but not highly insulated shielded cable like the 174U discussed earlier and start about 30cm. trim for tone shaping.

[giordydiver]

http://www.tube-town.net/ttstore/Cables ... :1483.html I have this cable but the Voltage Rating max is 50 / 75 V AC / DC..what do you thing?

[snakepit86]

from the Frank's intagram the Mark 7 mod

[herbvis]

Great find! Look at the 2ND stage coupling cap. It takes a little shortcut to the mixers. He showed me that one before. Looks like a resistor on the gain pot. Is that a cap underneath the resistor? Hard to make out. Interesting...

[budubum92]

Great find! Look at the 2ND stage coupling cap. It takes a little shortcut to the mixers. He showed me that one before. Looks like a resistor on the gain pot. Is that a cap underneath the resistor? Hard to make out. Interesting...

I believe that the second coupling should be just like the stock ones. Goes directly to the voltage dividers.

It seems to me this is thesame as #34. It has the resistor from wiper to ground. It still has tropical fish at third cathode.
0.1uf seems to be the second. The first electro cap cathode not sure what valur but has 47v on it?

[herbvis]

Great find! Look at the 2ND stage coupling cap. It takes a little shortcut to the mixers. He showed me that one before. Looks like a resistor on the gain pot. Is that a cap underneath the resistor? Hard to make out. Interesting...

I believe that the second coupling should be just like the stock ones. Goes directly to the voltage dividers.

It seems to me this is thesame as #34. It has the resistor from wiper to ground. It still has tropical fish at third cathode.
0.1uf seems to be the second. The first electro cap cathode not sure what valur but has 47v on it?

its a 25uf electro cap. that stage is the first stage, the resistor is 1.5k. the 2nd is 2.7/.68. The coupling cap does go to the voltage divider. He shared a pic with me that had the coupling cap take a similar shortcut to the voltage divider. it is set up that way to avoid noise. the 3rd is the signature 470n.

look at the gain pot. Under the added resistor you can see what looks to be the shielded cable soldered to the back of the pot, then there appears to be a black silver mica cap peeking out.what is that?

[snakepit86]

Great find! Look at the 2ND stage coupling cap. It takes a little shortcut to the mixers. He showed me that one before. Looks like a resistor on the gain pot. Is that a cap underneath the resistor? Hard to make out. Interesting...

I believe that the second coupling should be just like the stock ones. Goes directly to the voltage dividers.

It seems to me this is thesame as #34. It has the resistor from wiper to ground. It still has tropical fish at third cathode.
0.1uf seems to be the second. The first electro cap cathode not sure what valur but has 47v on it?

its a 25uf electro cap. that stage is the first stage, the resistor is 1.5k. the 2nd is 2.7/.68. The coupling cap does go to the voltage divider. He shared a pic with me that had the coupling cap take a similar shortcut to the voltage divider. it is set up that way to avoid noise. the 3rd is the signature 470n.

look at the gain pot. Under the added resistor you can see what looks to be the shielded cable soldered to the back of the pot, then there appears to be a black silver mica cap peeking out.what is that?

how do you know the values? ajajaaj the second cathode cap seems to be something like 100n/220, i think a 680n will be bigger.

The capacitor below the gain pot i think its going to the shield of gnd, a fixed low pass filter, cutting highs.

look at the phase inerter coupling caps, i think they are 100n, just like the 2 cathode.

Herb do you mind to draw a circuit?

[herbvis]

I checked those caps out on ebay. The phsysical size matches. The values are according to the mk7 schematic. The resistor on the pot appears to be a new addition to the mod. Maybe that particular amp needed it . I cant tell what the pi caps are, but isnt there a pic of levi with an amp he did that had all orange drop caps.. werent the pi caps .1's in that amp?

Interesting about the black mica cap on the pot. Could it be similar to a hot shield on the plate?
The other mica cap across the 470k going in to the gain pot has got to be 470pf. Any of those black mica caps that I have seen that are 1000pf and over are physically larger in size.
The tropical fish (value) is also present in every levi mod schematic or pic that I have seen. There is no doubt in my mind that it was in #36.

Anyone notice anything else interesting?

[budubum92]

I checked those caps out on ebay. The phsysical size matches. The values are according to the mk7 schematic. The resistor on the pot appears to be a new addition to the mod. Maybe that particular amp needed it . I cant tell what the pi caps are, but isnt there a pic of levi with an amp he did that had all orange drop caps.. werent the pi caps .1's in that amp?

Interesting about the black mica cap on the pot. Could it be similar to a hot shield on the plate?
The other mica cap across the 470k going in to the gain pot has got to be 470pf. Any of those black mica caps that I have seen that are 1000pf and over are physically larger in size.
The tropical fish (value) is also present in every levi mod schematic or pic that I have seen. There is no doubt in my mind that it was in #36.

Anyone notice anything else interesting?

yes on every levi mod that had only 3 gain stages yes there is a cap. but do that to a 4 gainstager then it would be too much mids and honk. maybe he compensated for something down the road for the extra effect of the last cap.

[bennyx]

I checked those caps out on ebay. The phsysical size matches. The values are according to the mk7 schematic. The resistor on the pot appears to be a new addition to the mod. Maybe that particular amp needed it . I cant tell what the pi caps are, but isnt there a pic of levi with an amp he did that had all orange drop caps.. werent the pi caps .1's in that amp?

Interesting about the black mica cap on the pot. Could it be similar to a hot shield on the plate?
The other mica cap across the 470k going in to the gain pot has got to be 470pf. Any of those black mica caps that I have seen that are 1000pf and over are physically larger in size.
The tropical fish (value) is also present in every levi mod schematic or pic that I have seen. There is no doubt in my mind that it was in #36.

Anyone notice anything else interesting?

470n on 820ohm is the secret for the "greenback tone".......if you don't use it the head don't sound like greenback....
as other mods, Frank increase the treble peaker value and remove bright cap on gain......Plessey caps is made in Italy...near my home, it's made by Marconi electronic devices ......

the silver mica on anode it's a anode bypass, don't have the same effect of shield trick, cut bass and treb and remove little bit of gain......

[dukeamps]

Benny the secret to greenback tone is, just use greenback speakers

[bennyx]

Benny the secret to greenback tone is, just use greenback speakers

I don't want to change your mind......but you are wrong ......34 and 36 sound the same with all speakers....same greenback approach.....just change eq on mids like a post production eq.......the taste of head voicing is the same......

34 sound like greenback approach also with V30....470n on 820 is the real guilty......move the mids in a greenback range voicing

https://www.ampbooks.com/mobile/amplifi ... alculator/

someone that has a 34 done well can confirm it

an example

https://www.youtube.com/watch?v=4PqlqMLoNRE

https://www.youtube.com/watch?v=dvvfsAtlILU

[dukeamps]

Benny the secret to greenback tone is, just use greenback speakers

I don't want to change your mind......but you are wrong ......34 and 36 sound the same with all speakers....same greenback approach.....just change eq on mids like a post production eq.......the taste of head voicing is the same......

34 sound like greenback approach also with V30....470n on 820 is the real guilty......move the mids in a greenback range voicing

https://www.ampbooks.com/mobile/amplifi ... alculator/

Benny you can say want you want, but G12H30 75hz are the right speakers, get yourself some nice nos Mullards, pre & power, 70s G12H30 75hz speakers, 70s JMP 100w amp, then you will find the real 36 mod, its not really that hard, you just need the right gear, forget all these fixed bright caps, three shield tricks, 250p33k ts, no bright cap, 10k third & .1u on the pres.

Here is the real tone, well for me anyway,

Nos Mullards pre & power, 76 JMP 100w, 70s G12H30 75hz speakers, this setup still gets the tone 30 years later, & I'm just recording it in my living room lol,

http://soundclick.com/share.cfm?id=13280279

[bennyx]

ok ok.....I did not want to quarrel.....think how you want

not 3 shield.....2